Patchwork [qom-cpu,04/11] target-i386: kvm: Enable all supported KVM features for -cpu host

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Submitter Eduardo Habkost
Date Jan. 4, 2013, 10:01 p.m.
Message ID <1357336872-7200-5-git-send-email-ehabkost@redhat.com>
Download mbox | patch
Permalink /patch/209553/
State New
Headers show

Comments

Eduardo Habkost - Jan. 4, 2013, 10:01 p.m.
When using -cpu host, we don't need to use the kvm_default_features
variable, as the user is explicitly asking QEMU to enable all feature
supported by the host.

This changes the kvm_cpu_fill_host() code to use GET_SUPPORTED_CPUID to
initialize the kvm_features field, so we get all host KVM features
enabled.

This will also allow use to properly check/enforce KVM features inside
kvm_check_features_against_host() later. For example, we will be able to
make this:

  $ qemu-system-x86_64 -cpu ...,+kvm_pv_eoi,enforce

refuse to start if kvm_pv_eoi is not supported by the host (after we fix
kvm_check_features_against_host() to check KVM flags as well).

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
Changes v2:
 - Coding style (indentation) fix

Cc: Gleb Natapov <gleb@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org
---
 target-i386/cpu.c | 2 ++
 1 file changed, 2 insertions(+)
Gleb Natapov - Jan. 6, 2013, 1:52 p.m.
On Fri, Jan 04, 2013 at 08:01:05PM -0200, Eduardo Habkost wrote:
> When using -cpu host, we don't need to use the kvm_default_features
> variable, as the user is explicitly asking QEMU to enable all feature
> supported by the host.
> 
> This changes the kvm_cpu_fill_host() code to use GET_SUPPORTED_CPUID to
> initialize the kvm_features field, so we get all host KVM features
> enabled.
> 
> This will also allow use to properly check/enforce KVM features inside
> kvm_check_features_against_host() later. For example, we will be able to
> make this:
> 
>   $ qemu-system-x86_64 -cpu ...,+kvm_pv_eoi,enforce
> 
> refuse to start if kvm_pv_eoi is not supported by the host (after we fix
> kvm_check_features_against_host() to check KVM flags as well).
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>

> ---
> Changes v2:
>  - Coding style (indentation) fix
> 
> Cc: Gleb Natapov <gleb@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Marcelo Tosatti <mtosatti@redhat.com>
> Cc: kvm@vger.kernel.org
> ---
>  target-i386/cpu.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index c49a97c..e916ae0 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -911,6 +911,8 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
>      /* Other KVM-specific feature fields: */
>      x86_cpu_def->svm_features =
>          kvm_arch_get_supported_cpuid(s, 0x8000000A, 0, R_EDX);
> +    x86_cpu_def->kvm_features =
> +        kvm_arch_get_supported_cpuid(s, KVM_CPUID_FEATURES, 0, R_EAX);
>  
>  #endif /* CONFIG_KVM */
>  }
> -- 
> 1.7.11.7

--
			Gleb.

Patch

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index c49a97c..e916ae0 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -911,6 +911,8 @@  static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
     /* Other KVM-specific feature fields: */
     x86_cpu_def->svm_features =
         kvm_arch_get_supported_cpuid(s, 0x8000000A, 0, R_EDX);
+    x86_cpu_def->kvm_features =
+        kvm_arch_get_supported_cpuid(s, KVM_CPUID_FEATURES, 0, R_EAX);
 
 #endif /* CONFIG_KVM */
 }